Recent Developments in CTE-Matched Composite Thermal Materials

Abstract

A surprisingly large number of engineered materials are available to the module and system packaging engineer that have been designed for a target coefficient of thermal expansion (CTE, stated both at room temperature and across a specified range of temperatures) and possessing bulk thermal conductivity values useful for device heat dissipation. There are continuing research and development programs for new forms and variations of such materials, intended to meet continuing demands for improvement on a spectrum of requirements. These requirements include higher bulk isothermal conductivity values, lower cost, lower CTE values, reduced density and weight, and, for certain types of applications, a target CTE and highly anisotropic property. This discussion seeks to identify both existing and common materials (for comparison purposes) and new developments that are being brought to market and/or are in production today. The purpose is to add to the design engineer’s tool kit for available materials of these types. In addition, high temperature effects on selected materials are illustrated.